The invention relates to piston and cylinder units comprising a cylinder barrel whose cylinder space contains a piston which is able to be displaced in the axial direction and runs on the peripheral guide surface of the cylinder space.
During the production of piston and cylinder units it has so far been necessary to fit the piston precisely in the cylinder space or the cylinder bore and for this purpose to precisely machine the surface of the piston so that it has a high quality finish, for the guiding or support function for the piston when displacement in the piston space is performed by its outer surface cooperating with the inner surface of the cylinder barrel which forms a guide or bearing surface. Elaborate manufacture results in high production costs and furthermore owing to the large area of contact between the piston and the cylinder barrel a heavy load will often lead to seizing of the piston, something that is more likely to be encountered when there are considerable changes in the environmental temperature of the unit.